Detail: an "instruction-fetch" response from mmioplatform to core should be an "InstFetch". This was true for successful fabric reads, but on error responses it was wrongly returned as a "DataAccess" response. This was causing a deadlock.
To get the instruction trace back, set verbosity to 1 in CommitStage.bsv. Regressions: RV64ADFIMSU_Tooba_verilator: 199/227 PASS (1 test hangs)